We present an atomistic model of pillared DNA nanotubes (DNTs) and their elastic properties which will facilitate further studies of these nanotubes in several important nanotechnological and biological applications. In particular, we introduce a computational design to create an atomistic model of a 6-helix DNT (6HB) along with its two variants, 6HB flanked symmetrically by two double helical DNA pillars (6HB+2) and 6HB flanked symmetrically by three double helical DNA pillars (6HB+3). Analysis of 200 ns all-atom simulation trajectories in the presence of explicit water and ions shows that these structures are stable and well behaved in all three geometries. Hydrogen bonding is well maintained for all variants of 6HB DNTs. We calculate the persistence length of these nanotubes from their equilibrium bend angle distributions. The values of persistence length are ~10 μm, which is 2 orders of magnitude larger than that of dsDNA. We also find a gradual increase of persistence length with an increasing number of pillars, in quantitative agreement with previous experimental findings. To have a quantitative understanding of the stretch modulus of these tubes we carried out nonequilibrium Steered Molecular Dynamics (SMD). The linear part of the force extension plot gives stretch modulus in the range of 6500 pN for 6HB without pillars which increases to 11,000 pN for tubes with three pillars. The values of the stretch modulus calculated from contour length distributions obtained from equilibrium MD simulations are similar to those obtained from nonequilibrium SMD simulations. The addition of pillars makes these DNTs very rigid. KEYWORDS:DNA nanotubes, molecular dynamics, persistence length, Holliday junctions. 3DNA is an excellent material of choice for the precise organization of chemical species on the nanoscale. [1][2][3][4] The specific base pairing rules that enable DNA to function as a biological information carrier also facilitate the construction of DNA assemblies in a programmable manner. The interstrand interactions and sticky ended cohesion of DNA molecules provide a scaffold for the synthesis of branched DNA nanostructures with excellent precision. 5 In the past few decades, various novel nanostructures such as cubes, 6 tetrahedra, 7 truncated octahedra, 8 icosahedra, 9 smiley faces, two dimensional arrays 10-13 and nanotubes [14][15][16][17] have been synthesized using the versatile DNA molecule. Nanomechanical devices have also been constructed using DNA motifs, extending their potential application to DNA nanorobotics. [18][19][20] The introduction of DNA origami 21 has significantly accelerated the synthesis of various DNA nanostructures.Looking forward to the application of DNA nanotubes (DNTs) in cellular drug delivery, researchers are investigating their self-assembly and interaction with lipid membranes. 22, 23 The development of techniques such as DNA origami along with computational tools such as caDNAno 24 and 3DNA 25 has made their fabrication and analysis fast and efficient. With a...

Compartment syndrome is a rare complication of spectrum of purple glove syndrome, seen as a side effect of intravenous phenytoin. This involves rapid discolouration of the involved limb along with edema and sometimes blistering of the skin also. Treatment is usually conservative and rarely requires surgery. We present a case of compartment syndrome following intravenous phenytoin administration and review of literature related to the case.

The present investigation reports the various pharmacokinetic parameters of immediate release aceclofenac tablets incorporating its inclusion complex with hydroxypropyl-β-cyclodextrin. The tablets were prepared using aceclofenac: hydroxypropyl-β-cyclodextrin in a 1:1 molar ratio by the direct compression method (TKN). The results were compared with those of the marketed brand (MKT) and pure drug (TAC). The P-values indicated that mean plasma concentrations were significantly different among all three formulations administered (P<0.05, P<0.01). TKN showed significantly higher plasma levels when compared to the pure drug (P<0.01). The C max and AUC (0-∞) of TKN were significantly higher (P<0.05) compared to the pure drug and marketed formulation. Furthermore, the first-order overall elimination rate constant (K el ) of TKN was also significantly higher (P<0.05) compared to the pure drug and its marketed formulation. These results suggested that tablets prepared by incorporating the AC-HPβCD inclusion complex (TKN) would provide a more rapid onset of pharmacological effects in comparison to the marketed formulation and pure drug.

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